PURPOSE: To enable a pipe to be cut easily and rapidly by turning a pantagraph mechanism of an L-shape at a low speed to allow the rod material provided at the terminal contact the surface of a rule plate and operating the sliding member and gas cutting nozzle at the end.

CONSTITUTION: In the case of cutting the circumferential wall of a pipe B square to its axial line, a rule plate 4 is so adjusted by an expander 9 that the surface thereof becomes square to the axial line of the pipe B. The terminal of a rod material 5 is always contacted with the surface of the rule plate 4 by a pressing mechanism 3 and a sliding member 6 is contacted with the outside circumference of the pipe B having been set so that a nozzle C is faced on the cutting line of the pipe B. Thence, a fusion cutting gas is burned in the nozzle C and a pantagraph mechansim 2 is turned at a low speed by a revolving shaft 1 in one direction, whereby the pipe B is fusion-cut by the nozzle C. To obliquely cut the pipe B, the rule plate 4 is beforehand adjusted by tilting so that it coincides with the angle thereof.